The various inventions disclosed herein relate generally to the superimposed presentation of relatively low-resolution or low-quality images, acquired in real time, onto relatively high-resolution or high-quality images acquired preoperatively.
Conventional fluoroscopy is widely used during medical procedures as a visualization and validation imaging tool for guiding medical instruments inside the human body. Although medical instruments like catheters, biopsy tools, etc., are clearly visible on a fluoroscopic picture, organic features such as soft tissue, blood vessels, suspicious tumor lesions etc., are quite transparent and hard to identify with conventional fluoroscopy. As such, frequently a higher quality diagnostic image is acquired, such as CT scan, prior to the operation.
Before a biopsy or therapeutic procedure, a physician studies the patient's CT scan and identifies the target area, such as an area containing a suspicious lesion. Based on his or her professional knowledge, the physician intuitively plans the upcoming procedure by estimating and memorizing the lesion's size, shape and location inside the soft tissue of the chest or abdomen.
Next a procedure is performed, such as a biopsy, which involves the introduction of a medical instrument into the target area. During the procedure, a fluoroscopic picture is used by physician to aid the maneuvering of medical instruments inside the soft tissue towards the target area. The medical instrument is clearly visible but the tissue is transparent.
Hence, the current method has the following disadvantages:                1) When performing diagnostics of suspicious area, a common practice is to use multiple biopsies to increase the diagnostic success probability. This technique increases the procedure time and radiation exposure time, thereby increasing the risk to the patient and attending personal of potential X-ray exposure-related issues.        2) The existing method is inaccurate in locating the position of the medical instrument relative to the lesion because:                    a. Information regarding lesion location and size, such as that potentially available from a CT image, are not utilized by the diagnostic and therapeutic procedures that are performed under a fluoroscope.            b. The targeted tissue is rarely seen on a fluoroscopic image.            c. The fluoroscopic image is designed for visual perception and not intended to provide accurate, measurable information.            d. A fluoroscopic image is two-dimensional, while an internal lesion is located in three-dimensional space.                        3) There is a potential risk of excessive bleeding or pneumothorax following biopsy, caused by implement injuries to internal organs or blood vessels not seen by the fluoroscope.        4) Internal organs and other tissues move due to breathing, heart activity, etc. Because these features are transparent to a fluoroscope, it is difficult or impossible to be sure that the path of a medical instrument remains as planned toward the targeted area by monitoring a fluoroscope alone. Observing external body movement does not always provide an accurate indication of internal organ movement.        
Moreover both due to the limited CT resolution and low radio-opacity of the bronchial tissue the peripheral bronchial airways are not likely to be seen using CT, especially when using a low-dose CT, which is much more commonly used, less expensive, and safer for the patient than a high-dose CT. However when targeting the small peripheral lesions it is essential to identify and utilize the path leading to peripheral lesion.
These inaccuracies result in a low diagnostic success rate and, therefore, such procedures are usually reserved for larger lesions.
One aspect of the present invention is to provide a method that improves upon conventional bronchoscopy procedures, whether using existing medical equipment or the apparatus of the present invention.
Another aspect of the present invention is to provide a method that improves upon conventional biopsy or therapeutic procedures in organs that are not seen under fluoroscopy, whether using existing medical equipment or the apparatus of the present invention.
The proposed method improves the quality of fluoroscopic imaging to an extent that allows fluoroscopic imaging to be used as an accurate measuring modality. Hence, the non- or minimally-invasive and inexpensive attributes of fluoroscopic imaging procedures are utilized. The proposed method is mostly suitable to assist the diagnostic and therapeutic procedures in the lungs, liver and kidney.
One aspect of an embodiment of the present invention navigates a medical instrument to a targeted anatomy extracted from high-quality volume data.
Another aspect of an embodiment of the present invention provides a real-time image of a static or moving medical instrument and a targeted anatomical feature in proximity thereto.
Yet another aspect of an embodiment of the present invention provides a method and apparatus that combines single or multiple 2D fluoroscopic images with previously acquired high-quality volume data.
Another aspect of an embodiment of the present invention provides a method and apparatus that dynamically determines the most visually informative combination of single or multiple 2D fluoroscopic images with previously acquired high-quality volume data on an application-specific or user-specified basis.
One aspect of the present invention provides various embodiments of catheters and endoscopes that allow 3D shape data to be determined from single or multiple 2D fluoroscopic images.
Another aspect of an embodiment of the present invention provides an apparatus and method for maintaining an accurate registration between a dynamic fluoroscopic image and a static CT image.
Additional aspect of this invention present the way of local improvement to the anatomy extracted from high-quality volume data of limited resolution.
Yet another aspect of the invention provides a technique for improving the coverage area of a low-dose CT scan, such that a high-dose CT scan can be avoided.